Out of curiousity, did you prefix "Student" to your call-sign? I appreciate that in Australia, this might not be the done thing, but in the UK whenever a student is flying solo he addresses himself as "Student G-ABCD" where G-ABCD is the registration of the aircraft. The advantage of this is that its like wearing 'L Plates' on the radio, and alerts the ATCO/FISO/&c. that you are still under-training for you PPL, and their attitude towards you changes, but not in a patronising or condescending way.
Usually, they'll make more of an effort to speak slower and avoid complicated instructions. Also, in this instance if the Cessna ahead realised that you were a student, he might have decided to leave the circuit and re-join after you had landed. Then again, he might not have.
In speculating on who was in the wrong, if there was a mid-air collision then I think the fault would be attributed to your error; because you failed to maintain visual contact with the Cessna, and failed to obtain that visual before turning your aircraft. Like Thing said, this is easy to state whilst sitting in the comfort of an armchair on terra firma, but something else when in the air on the most demanding part of a flight.
It would be interesting to hear an instructor's opinion, though.